The casting equipment is used in the way that the cellular lower part is placed on a casting board disposed upon a vibration table with the upper part lying in an elevated position above the lower part. A concrete supply vehicle is guided in along the upper side of the lower part in the space below the upper part, thus pouring concrete into the casting cells and filling these with concrete. After filling, the supply vehicle is drawn out, and the upper part is lowered until the said thrust plates hit the concrete surfaces in the respective casting cells. Then, the upper part is used as a multi-pressure piston for compressing the concrete mass in the individual casting cells; this occurs under strong vibration of the casting equipment for separating air from the concrete mass. Hereby, the cast items are compressed for the desired compact block form and uniform thickness. Subsequently, the upper part is retained at its final level relative to the lower part, and the lower part is acted on by force and elevated from the casting board, whereby the cast items, which, by the pressure maintained from the upper part, do not participate in this elevation, and will remain standing on the casting board during the decasting concerned. When the decasting has ended by the ejection of the lower part to a position, in which its underside is elevated to at least the level of the pressing plates of the upper part, the semi-solid cast items can be removed from the vibrating table by ejection after elevating the upper part, after which a new casting cycle may begin after lowering the bottom part to the casting board and elevating the upper part to its starting position.
Any design and height of concrete products which are cast in a concrete casting machine require special casting equipment. As the concrete casting machine, merely by changing the casting equipment, is able to produce another product, e.g. another shape or height of the concrete product, it is necessary that the casting equipment easily can be changed in the concrete casting machine. Equipment for a quick retention and letting go of the casting equipment in concrete casting machines exist, see for example DK 171 553 and the German utility model G 88 15 262.6.
From DE 90 04 234 U is known a box formed construction which detachably may be fastened to a casting upper part in a concrete casting machine by means of a locking device with a complementary locking element.
Traditionally, the upper part for these retention systems is supplied with a welded superstructure or different types of fittings which precisely fit one type/make of concrete casting machine. This means that these superstructures are especially designed for the individual concrete casting machine and cannot easily be changed to another type/make of concrete casting machine. Furthermore, other factors are also significant, e.g. the height of the superstructure also often varies depending on the different makes of concrete casting machines, and even the form varies depending on which product the form is designed to produce.
As mentioned in the prior art described above, the mounting of forms in concrete casting machines is typically carried out by means of hydraulic or pneumatic cylinders which retain the casting upper part against a heavy retainer plate in the concrete casting machine. In the casting upper part there are typically two or three slots or rows of fittings wherein “mushrooms” mounted on each cylinder trundle by means of hydraulic or pneumatic pressure in the cylinders retain the casting upper part in the machine.
One disadvantage by several of the existing types of superstructures is the material stress which occurs in the form during the production in connection with the welding process. This stress may, however, be removed by a subsequent cost-increasing heat-treatment process.